This invention is directed generally to a seat and back construction for a passive ergonomic chair, primarily a chair of the office type.
This invention is more specifically directed to a passive ergonomic office chair of the knee-tilt type in which the horizontal pivoting axis of the seat and back is located near the front of the chair. However, the invention is not limited to chairs of these specific types since aspects of the invention may have application to other types of office chairs and other chairs of all kinds.
The invention is particularly adaptable to passive ergonomic chairs of the type shown and described in U.S. Pat. No. 4,660,887, issued to the assignee of this invention. Some embodiments of ergonomic chairs described in said patent have a resilient and flexible inner shell formed of plastic in which openings in the inner shell provide flexible, cantilevered support members in the seat and back portions of the inner shell. These flexible, cantilevered support members enable the plastic inner shell to more closely and comfortably conform to the body of a user.
An object of this invention is to mount a resilient and flexible inner shell on the structure of a knee-tilt chair so as to enhance the ergonomic features of the inner shell.
Another object of this invention is to mount a resilient and flexible inner shell having flexible, cantilevered support members on a chair pedestal post in such a manner that the mounting structure does not interfere with the flexing of the flexible, cantilevered support members.
Another object of this invention is a knee-tilt chair having a resilient and flexible inner shell in which the load applied by an occupant to the back portion of the inner shell is transferred to the seat-supporting structure through an outer shell that is much more rigid than the inner shell.
Another object of this invention is a chair seat and back structure having inner and outer shells in which the outer shell supports and strengthens the back portion of the inner shell.
Other objects of this invention may be found in the following specification, claims and drawings.